title: Comparison of tonal response properties of primary auditory cortex neurons of adult rats under urethane and ketamine anesthesia.
abstract: OBJECTIVE
  To compare tonal response properties of neurons in the primary auditory cortex of Sprague-Dawley rats anesthetized with urethane and ketamine-xylazine.
  
  
  METHODS
  Forty-five female Sprague-Dawley rats (200-250 g) were randomized into two groups and anesthetized with urethane or ketamine-xylazine. Tone pips were chosen as the stimuli to obtain the action potentials of the single neurons by in vivo cell-attached recording. The features of the action potentials were extracted with Matlab software to comparatively analyze the acoustic response properties of the neurons between the two anesthetic groups.
  
  
  RESULTS
  The Q values and the characteristic frequencies were independent of the types of anesthetic agents, but with urethane anesthesia, the neurons tended to have higher minimum thresholds, lower spontaneous firing rates, longer response latencies, and more frequent occurrence of tuning with stronger inhibition compared to those in ketamine-xylazine group.
  
  
  CONCLUSIONS
  Urethane and ketamine might have no obvious impact on the transmission pathway of frequency tuning from the periphery to the auditory cortex, but neurons from rats with urethane anesthesia receive enhanced inhibition mediated by the interneurons or have a lower intrinsic excitability.
authors.affiliation: Department of Physiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou 510515, China. huanglingyueliyan@yahoo.com.cn
authors.forename: Lingyue
authors.initials: L
authors.lastname: Huang
authors.forename: Lin
authors.initials: L
authors.lastname: Bai
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhao
authors.forename: Zhongju
authors.initials: Z
authors.lastname: Xiao
mesh_terms: D000777:Anesthetics / Q000494:pharmacology*; D000818:Animals; D001301:Audiometry, Pure-Tone; D001303:Auditory Cortex / Q000187:drug effects / Q000502:physiology*; D005260:Female; D007649:Ketamine / Q000494:pharmacology*; D009474:Neurons / Q000187:drug effects*; D051381:Rats; D017207:Rats, Sprague-Dawley; D014520:Urethane / Q000494:pharmacology*
chemical_list: D000777:Anesthetics; D014520:Urethane; D007649:Ketamine